The numbers correspond roughly to figures released by the Pentagon this year in response to a Freedom of Information Act request submitted by the Associated Press. Iraq Body Count, a London-based organization that has tracked civilian casualties, said it had identified 15,000 previously unrecorded deaths in the newly released files.

Beyond the broad outlines of the casualty counts, the records offer glimpses of the circumstances in often-heartbreaking detail.

The logs document the killing of as many as 681 civilians at checkpoints - "escalation of force incidents" in the military parlance - where troops fearing suicide bombers opened fire on often-confused drivers who did not know how to act when approaching soldiers, especially at night.

The Guardian reported that in September 2005, near Musayyib, south of Baghdad, two U.S. soldiers opened fire on a car when it continued to approach them after the driver ignored flashing lights and warning shots. A man and his wife were killed, and their 9- and 6-year-old children were wounded.

A month later, again at night, two children were killed in Baghdad when a female driver continued to approach a checkpoint after a single warning shot was fired.

The files also record the bloody toll of soldiers and civilians killed by insurgents' increasingly sophisticated use of roadside bombs: 31,780 deaths were attributed to improvised explosive devices.

The logs record numerous and often horrifying instances of torture and abuse by Iraqi military and police forces, many of which U.S. troops chose to ignore because of orders to refer such matters to senior Iraqi officers, according to the Guardian's reading of the documents.

In one case, in August 2009, a U.S. military doctor found "bruises and burns as well as visible injuries to the head, arm, torso, legs and neck" on the body of a man that police said killed himself.

In another case, in the northern Iraqi city of Mosul, coalition forces reported that three Iraqi officers poured acid on the hands of a man and cut off some of his fingers. Two years after the event no arrests had been made, according to one of the documents.

The logs do record attempts by U.S. and coalition forces to stop the abuse by conducting spot-checks on Iraqi facilities where they found prisoners "covered in injuries," the Guardian reported.

But U.S. soldiers often could do little more than demand that the torture stop. An order, issued in June 2004, instructed troops to make an initial report but not to investigate breaches of the laws of war "unless directed by HQ," according to documents cited by al-Jazeera and the Guardian.

The records do not represent the first time that abuses by Iraqi authorities have been disclosed. In November 2005, U.S. troops discovered a Ministry of Interior-run prison in which more than 150 Sunni inmates were being held without charges. The prisoners were emaciated and several lifted up their shirts to show bloody whip marks where they had been beaten, according to U.S. officials who took photographs of the facility. News of the facility was leaked to U.S. and Iraqi newspapers, and U.S. commanders confronted then- Prime Minister Ibrahim al-Jafari about the facility. No punitive action was taken.